Translation: CAMBION, -- Child of Demons. Delancre and Bodin think that incubus demons could unite with succubus demons, and that born of their exchange were hideous children which are called cambions.....

The word cambion previously appeared on an early 1st century AD inscription in Gaul (Roman France). Linguist Benjamin W. Forston IV opines that:

...cambion is from the Celtic root -kamb 'crooked', also referring to back and forth motion and exchange. It is ultimately the source for English change via late Latin cambiare, a borrowing from Celtic.[2]

Given the above, it's probable that the word, as de Plancy defined it in 1818, is a cognate for changeling.

Moreover, to beget a child is the act of a living body, but devils cannot bestow life upon the bodies they assume; because life formally proceeds only from the soul, and the act of generation is the act of the physical organs which have bodily life. Therefore bodies which are assumed in this way cannot either beget or bear.[3]

Because of this inability to create or nurture life, the method of the creation of a cambion is necessarily protracted. A succubus will have sex with a human male and so acquire a sample of his sperm. This she will then pass on to an incubus. The incubus will, in his turn, transfer the sperm to a human female and thus impregnate her.

Yet it may be said that these devils assume a body not in order that they may bestow life upon it, but that they may by the means of this body preserve human semen, and pass the semen on to another body.[3]

The text goes on to discuss at great length the arguments for and against this process being possible, citing a number of biblical quotations and noted scholars in support of its arguments, and finally concludes that this is indeed the method used by such demons.

In the Encyclopedia of Occultism and Parapsychology the cambion is said to be the direct offspring of the incubus and the succubus, foregoing any need for human involvement. This same incarnation retained the absence of breath or a pulse until seven years of age, but was said to also have been incredibly heavy (even too heavy for a horse to carry) and to have cried upon being touched.[4]